Growth and biochemical profiling of marine microalgae Chlorella salina with response to nitrogen starvation

ABSTRACT The present study aimed at investigating nitrogen stress-induced biochemical changes in the marine microalgae Chlorella salina. The algae were grown in N free medium (N − ) in order to study the proximate composition via the determination of protein, lipid and carbohydrate. The chemical constituents of this algae were determined using GC-MS and mineral content was analysed using Inductive Coupled Plasma-Mass Spectrometry (ICP-MS). From the results, the proximate analysis showed increased lipid (34.77 ± 0.6%), followed by carbohydrate (26.21 ± 0.2%) and protein (5.4% dry weight). The chemical constituents of C. salina were successively extracted with diethyl ether, hexane, chloroform, acetone and methanol. The extract percentage varied greatly between various solvents, with the highest one (4.68%) recorded for methanol. A total of 35 compounds were identified from the extracts and the identified chemical groups included ketones, terpenes, fatty acids (FA), fatty alcohols and esters derived fatty acids and/or dicarboxylic acid and hydrocarbons. The methanol extract consisted of FA (35%), amino acids and N-containing metabolites (7%), fatty alcohols (8%), organic acids (3%) and hydrocarbons (80%). The algae exhibited high amounts of Mg (54.079 mg/50 g) followed by C (17.341 mg/50 g), S (5.702 mg/50 g) and Na (3.275 mg/50 g). These results demonstrated a strong correlation between the nitrogen content and lipid accumulation, hence showing that Chlorella salina could serve as a potential candidate for biodiesel production.